Déagol, was the StoorHobbit who had found the One Ring while diving in the Gladden river (a tributary to the Anduin) with his friend Sméagol (and "evidently a relative", as told by J.R.R. Tolkien in Letters #214, p. 292). Sméagol (later known as Gollum) demanded the ring and murdered Déagol when he refused to give it to him.

Etymology

Déagol is an Old English translation of the "original" Westron name 'Nahald'. Both names carry the meaning "apt to hide, secretive".